You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaicontinue=".303_British.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="202" ns="6" title="File:(Crafting) Hellsing Arms Joshua.jpg" />
      <page pageid="203" ns="6" title="File:(Crafting) Scaramanga s Golden Gun.jpg" />
      <page pageid="3352" ns="6" title="File:.22 Long Rifle.jpg" />
      <page pageid="6277" ns="6" title="File:.243 Winchester.jpg" />
      <page pageid="3354" ns="6" title="File:.260 Remington.jpg" />
      <page pageid="3372" ns="6" title="File:.30-06 Springfield.jpg" />
      <page pageid="3392" ns="6" title="File:.30-30 Winchester (JSP).jpg" />
      <page pageid="3362" ns="6" title="File:.300 AAC Blackout.jpg" />
      <page pageid="6280" ns="6" title="File:.300 RSAUM (JSP).jpg" />
      <page pageid="3367" ns="6" title="File:.300 Winchester Magnum.jpg" />
    </pages>
  </query>
</api>